Method and crane for installing, maintaining and decommissioning wind turbines

ABSTRACT

Method and apparatus for installing, maintaining and decommissioning wind turbines, both onshore and offshore, comprises a crane having extendable legs that allow it to climb a tower that it is erecting in sections by engaging the tower by friction or mechanical interference. The crane may carry the wind turbine nacelle on its upper members during construction of the tower and may be fitted with a crane for handling tower sections, or it may carry an “A” crane for lifting the nacelle and its components once the tower is complete or for constructing heavy maintenance. The crane may be fitted with various lifting and handling means to facilitate maintenance or the installation, maintenance or removal or airfoil rotor blades.

The present invention relates to a self-installing tower, nacelle andblades which may be used in the onshore and offshore wind farm industry.

The use of fossil fuels such as coal, oil and natural gas, has becomeincreasingly undesirable as evidence has emerged that the burning ofthese fuels is a key factor in environmental problems, such as globalwarming, air quality deterioration, oil spills and acid rain. Theseproblems, together with the depletion of fossil fuel resources, haveencouraged the search for alternative energy resources.

Wind energy is recognised world wide as a proven technology which can beutilised to meet the world's increasing electricity demands in asustainable economical and, most importantly, environmentally friendlymanner. In particular, wind power can be used to generate electricitywithout air emissions, water pollution or waste products, and cangreatly reduce the pollution which is currently generated by fossilfuels.

As a result of its advantageous properties, wind energy is currently thefastest growing source of electricity in the world. However, theerection of onshore wind farms is often controversial due to the visualimpact of large and cumbersome wind turbines, which are visible formiles around. Often, the erection of wind farms is opposed by residentsof nearby populated areas who regard them as unsightly or feel thattheir presence will reduce property values in the area. In addition, avariety of restrictions have affected the construction of these windfarms, including planning constraints and restrictions on the visualimpact and sound emissions from the turbines.

Because of these underlying problems, the idea of taking the windindustry offshore has developed. Offshore wind farms have minimalenvironmental effects and do not encounter the same planningrestrictions or difficulties with nearby residents that have arisen withthe development of onshore wind farms. As a consequence, the size andsound emissions of the farms do not have to be strictly regulated andmuch larger multi-megawatt machines can be used. In addition, the sizeof the offshore resource is huge, even when restrictions such asshipping lanes, areas of limited sea depth and known dumping grounds aretaken into account.

Whilst the erection of wind farms offshore has some advantages overon-land farms, construction of the turbines used to generate electricityis more expensive than onshore farms. In fact it is estimated thatcapital costs are in the region of 30% to 50% higher offshore due to thelarger machine size, maintenance and operational costs, including thecost of transporting and installing the wind turbines (including thetowers) at sea. It will be appreciated that the construction of thewind-towers, delivery to site and assembly of these large machinesrequire specialised equipment and this greatly increases the cost ininstallation, maintenance and decommissioning an offshore farm.

A problem with wind turbines is that they are big, and produce arelatively small amount of power (revenue). Therefore, they need to beinstalled as efficiently and cheaply as possible, whilst at the sametime minimising the risks to personnel. The construction industry as awhole is one of the most dangerous commercial activities undertaken inEurope, with the wind industry being no different. Given the low energydensity of wind generation, poor safety statistics would mean that theindustry as a whole would run the risk of being seen as a dangerousmeans of generation when measured on a “per unit of power generated”basis. Apparatus is therefore required to make construction of windfarms safer and deliver improved cost, safety and environmentaloutcomes. They should ultimately operate very reliably for many years.

At present, a commonly used method for constructing offshore windturbines uses a floating crane vessel. Typically a specially adaptedship is piloted to the area where the turbine is to be constructed.Generally as a result of the size of the crane and tower structure theymust carry, these vessels are large in size, and thus relativelyexpensive to use. Once the vessel has reached the area where the turbineis to be positioned, a concrete structure often known as a “gravityfoundation” is placed onto the seabed. A pylon-like turbine tower isthen fitted onto the concrete foundation using the cranes, the turbinetower carrying the blades which spin upwind of the tower itself.However, this process incurs significant costs as it is necessary forthe crane carrying vessel to be of a sufficiently large size to carrythe pylon-like turbine tower and the vessel must remain in the area inorder to support the operation.

It is therefore an object of the present invention to provide aself-installing or self-erecting wind tower, nacelle and blades, whichcan be erected in a manner, which is easier and cheaper thanconventional wind towers, nacelles and blades. Particularly it is anobject of the present invention to provide a self-installing orself-erecting wind tower which is reversible, i.e. can be dismantled,either in entirety or in part, as easily as it can be erected, iscomplete and “self sufficient”—i.e., can be built from an alreadyconstructed structure.

It is a particular object of the present invention to provide a windtower, which can be self-erected both offshore and onshore without theneed for specialist vessels or cranes.

According to the present invention there is provided apparatus for usein the onshore and offshore wind farm industry, said apparatuscomprising a jacking crane and a plurality of tower sections which canbe combined to erect a tower on which a nacelle and one or more bladescan be mounted using the same jacking crane.

Advantageously the jacking crane can be extended and climb upwards onthe tower as the tower is erected from the tower sections and is used toposition each of the tower sections during erection.

The tower is erected from the tower sections on a foundation platform.The jacking crane, tower sections and nacelle may be attached to orloaded onto the foundation platform before it is towed to the offshorelocation. Alternatively, the jacking crane, tower sections and nacellemay be loaded onto the foundation platform after it has been towed tothe offshore location.

Preferably the nacelle is positioned on top of the jacking crane. Wherethe jacking crane, tower structure and nacelle are loaded onto thefoundation platform after it has been towed to the offshore location,the jacking crane may be transferred from a vessel such as a ship orboat onto the foundation platform with the nacelle positioned on top ofthe jacking crane.

Most preferably the jacking crane acts as a motion compensation systemduring transferral from the vessel to the foundation platform.

The jacking crane may be hydraulically operated.

The jacking crane comprised a number of legs which can extend andretract. Preferably the jacking crane has four legs.

The tower sections may be approximately 10-25 metres in length.

Preferably the tower sections are air and water-tight, or can containbuoyancy units. Most preferably the tower sections are buoyant.Advantageously, this aids towing of the foundation platform to theoffshore location.

Preferably the jacking crane has a winch or which can be used to lifteach of the tower sections into position, on top of the previous towersection. The winch may be located within the nacelle.

The tower sections may be mounted on or attached to the foundationplatform. Alternatively, the tower sections may be transferred from avessel onto the foundation platform.

Optionally the nacelle may rotate on top of the jacking crane tofacilitate lifting operations.

Optionally the nacelle may be equipped with a winch or crane intended toassist with the installation of the nacelle or blades and theirsubsequent maintenance or replacement of the equipment within thenacelle or blades and then may be used to assist installation.

Optionally a boom may be attached to the jacking crane.

Optionally offshore the apparatus may also comprise a seawater ballastto counterbalance the boom.

Preferably the jacking crane is securely anchored to the tower duringand after erection and may have a mechanism to prevent detachment fromthe tower. The tower sections may be provided with purpose builtattachment points, which are adapted to receive the jacking crane.

Optionally the purpose built attachment points are pockets. The jackingcrane may have a first and second grip assembly which are adapted to fitinto the pockets.

Optionally the jacking crane may have one or more clamps, which engagethe tower sections. Advantageously this provides a secure and safeanchorage of the jacking crane to the tower.

Preferably the one or more clamps grip the tower sections by compressionand friction.

The one or more clamps may include contact pads, which are made from acompliant material such as polyurethane. The contact pads can be broughtinto contact with one of the tower sections and will develop verticalfrictional resistance upon the application of pressure.

Preferably the one or more clamps are mounted on an arrangement ofstruts, ties and beams which can be adjusted to accommodate a change inthe cross section of the tower or tower sections. In this manner thejacking crane can be adapted for use on a variety of wind turbine towerdesigns, or on a tapered wind turbine tower.

Preferably the contact pads are mounted on a flexible backing substratethat is tensioned at the ends. Preferably the flexible backing substratecontacts the tower in a plurality of locations or sections to provideeven distribution of load.

Preferably the length of the flexible backing substrate can be alteredto ensure the clamp maintains a secure fit to the tower. In a preferredembodiment this is achieved by the inclusion of rollers or sprockets.The ends of the flexible substrate are preferably made from, or coveredwith a complaint material and are adapted to be passed around therollers or sprockets which rotate as the length of the substrate isaltered.

Preferably the one or more clamps can be locked.

Preferably the tower sections have means for improving the attachment ofthe jacking crane. For example they may have a high grip surfaceachieved by the use of anti-slip paint or glue-on grip strips.

Mechanical toothed wedges may also be incorporated into the tower, towersections, jacking crane or clamps which engage a wedging action betweenthe tower and jacking crane.

Preferably the jacking crane is also used to transport the blades up thetower, for attachment to the nacelle. This process can also be carriedout in reverse to transport the blades down the tower duringdecommissioning.

The jacking crane may also be used for maintenance purposes.

Preferably the jacking crane can be connected to a variety of interfacetools. For example, the jacking unit may be adapted to carry tools,which are used for inspection and/or replacement and/or repair of theblades, nacelle or tower sections.

The jacking crane may comprise framework or a crane capable of plumbingor reaching into the nacelle.

The framework or additional crane can lift the nacelle or a subcomponent of the nacelle. Advantageously this allows the nacelle to belifted after the tower is completed.

The framework or additional crane can also be used for maintenance ofthe tower and tower sections. Optionally the framework or additionalcrane is extendible.

Where the jacking crane comprises a crane, said crane may be a knuckleboom crane.

The jacking crane may comprise a working platform and facilities forconstruction or maintenance personnel. These may be testing, monitoring,or service facilities, or welfare facilities for personal use.

According to a second aspect of the present invention, there is provideda method for installing the apparatus of the first aspect of the presentinvention in an offshore location, the method comprising the steps of:

-   (a) loading or attaching tower sections on to the foundation    platform;-   (b) towing the foundation platform to an offshore location using a    transportation vessel;-   (c) anchoring the foundation platform in the offshore position,    removing buoyancy from tower sections or other buoyancy units    (possibly by flooding);-   (d) transporting the jacking crane and nacelle from the    transportation vessel to the foundation platform;-   (e) removing the transportation vessel, if required;-   (f) extending the jacking crane vertically;-   (g) winching a first tower section from the foundation platform into    position with the jacking crane;-   (h) extending the jacking crane;-   (i) winching a second tower section from the foundation platform    into position with the jacking crane and on top of the first tower    section;-   (j) repeating steps (f) to (i) with further tower sections to erect    a tower; and-   (k) mounting turbine blades on to the nacelle.

The tower sections may be used to provide buoyancy to foundationplatform as it is towed to the offshore location.

Optionally the transportation vessel may be removed during anchoring ofthe foundation platform, and may return for step (d).

Preferably the jacking crane is used to raise the turbine blades up tothe nacelle. The winch in the nacelle may be used to transport theblades from the boat to the platform.

The method may be automated.

The method may be controlled by remote control.

According to a third aspect of the present invention there is provided amethod for installing the apparatus of the first aspect of the presentinvention on an offshore foundation platform, the method comprising thesteps of:

-   (a) towing a foundation platform to an offshore location using a    transportation vessel;-   (b) transporting the jacking crane and nacelle from the transport    vessel to the foundation platform;-   (c) transporting a first tower section onto the foundation platform    from the transportation vessel;-   (d) positioning the first tower section within and attached to the    jacking crane;-   (e) transporting a second tower section onto the foundation platform    from the transportation vessel;-   (f) extending the jacking crane;-   (g) winching the second tower section into position on top of the    first tower section within the jacking crane;-   (h) repeating step d) to f) with further tower sections to erect a    tower;-   (i) transporting a blade onto the foundation platform for mounting    on the nacelle from the transportation vessel, possibly using winch    inside nacelle;-   (j) moving the jacking crane up the tower to a position where the    blade can be mounted on the nacelle; and-   (k) repeating steps g) to h) for subsequent blades.

The method may be automated.

The method may be controlled by remote control.

According to a fourth aspect of the present invention, there is provideda method for installing the apparatus of the first aspect of the presentinvention on an foundation platform, the method comprising the steps of:

-   (a) loading the nacelle, tower sections and jacking crane onto an    foundation platform;-   (b) towing the foundation platform to an offshore location using a    transportation vessel;-   (c) anchoring the foundation platform to the sea bed at the offshore    location;-   (d) removing the transportation vessel;-   (e) extending the jacking crane;-   (f) winching a first tower section from the foundation platform into    position with the jacking crane;-   (g) extending the jacking crane;-   (h) winching a second tower section from the foundation platform    into position with the jacking crane and on top of the first tower    section;-   (i) repeating steps (e) to (h) with further tower sections to erect    a tower;-   (j) mounting the nacelle on the top of the tower; and-   (k) mounting turbine blades on to the nacelle.

The method may be automated.

The method may be controlled by remote control.

Preferably the jacking crane is used to raise the turbine blades up tothe nacelle. The winch in the nacelle may be used to transport theblades from the boat to the platform.

According to a fifth aspect of the present invention, there is provideda method for installing the apparatus of the first aspect of the presentinvention on a foundation platform or other foundation, the methodcomprising the steps of:

-   (a) delivering the nacelle, tower sections and jacking crane over a    foundation platform or other foundation using a transport vehicle;-   (b) lifting the nacelle onto the foundation platform or foundation;-   (c) removing the transport vehicle;-   (d) assembling crane and jacking crane;-   (e) extending the jacking crane;-   (f) delivering tower sections to the foundation platform or    foundation using a transport vehicle;-   (g) winching a first tower section from the transport vehicle using    crane;-   (h) sliding the first tower section into position within the jacking    crane using the crane;-   (i) supporting the nacelle on the tower section whilst adjusting    jacking crane to provide clearance for one or more clamps;-   (j) attaching clamps to securely and safely anchor jacking crane to    tower;-   (k) repeating steps (g) to (j) with further tower sections to erect    a tower;-   (l) mounting the nacelle on top of the tower; and-   (m) mounting turbine blades on to the nacelle.

An embodiment of the present invention will now be described by way ofan example only, with reference to the following Figures, in which:

FIG. 1 is a schematic view of the vessel in position next to anfoundation platform ready for the erection of the self-installing towerin an offshore environment according to the preferred embodiment of thepresent invention;

FIGS. 2 to 22 are schematic views showing installation of theself-installing tower;

FIG. 23 is a schematic view of the self-installing tower when installedand when ready for attachment of the turbine blades;

FIGS. 24 to 30 are schematic views of the turbine blades being attachedto the self-installing foundation platform;

FIG. 31 shows a foundation platform with tower sections attached beingtowed to an offshore location;

FIG. 32 shows the foundation platform of FIG. 31 after thetransportation vessel has left and being anchored in place;

FIGS. 33 and 34 show the nacelle and jacking crane being loaded onto thefoundation platform; and

FIGS. 35 to 46 show the tower being erected.

FIGS. 47 to 58 illustrate a method of erecting a wind turbine system onan foundation platform or other foundation.

FIGS. 59 to 67 are schematic drawings of the framework and jacking cranein position with the tower and tower sections.

The self-installing wind energy tower, with nacelle and blades can beerected in an onshore and offshore position in a first mannerillustrated in FIGS. 1 to 14. The Figures illustrate the apparatus in anoffshore environment, although use in an onshore environment is alsopossible. Referring firstly to FIG. 1, in one embodiment, vessel 1 has asmall crane 2 which is used to lift the self installing tower, nacelleand blades onto an installation (working) platform 3. The foundationplatform will be secured in position on the ocean bed 4, and testedprior to construction of the remaining parts of the finished windturbine. The apparatus described in the present Application isparticularly adapted for erection on the foundation platform describedin the Applicant's co-pending UK Patent Application No 0206569.6 andInternational Application No GB2003/001159. It is envisaged that theapparatus described in the present invention is suitable for use in bothoffshore and onshore locations. The apparatus brings significant costsavings by eliminating the requirement for large cranes, both onshoreand offshore.

In the first step shown in FIG. 2 a jacking crane 5, together with thenacelle 6 of the turbine is transferred onto the foundation platform 3.The jacking crane acts as a motion compensation system when it isinitially transferred to the platform with the nacelle on top. Thiseffectively means that the nacelle can be transferred from vessel 1 ontothe foundation platform ready for erection in poorer weather conditions(i.e. worse sea states) than otherwise possible. Thus, offshore workwill not be disrupted.

One of the essential requirements for the jacking crane hereindescribed, is that it must have a secure and safe anchorage to thetower. This ensures that the turbine is erected safely and efficientlyand allows cranes and other construction operations to be supported fromthe frame.

The jacking crane, as illustrated in the diagrams, comprises a framesupporting four legs (although the number of legs is not limited tothis) which can extend and retract. These are attached to upper andlower grip assemblies that can be moved relative to each other by theactuation of the jack legs. The grip assemblies grasp the tower usingarms that fit into pockets in the tower sections. The top works of thedevice contains winches and a trolley to mechanically handle the towersections into place under the nacelle for bolting to sections already inplace.

The apparatus and method described in the present Application may beused, not only to construct and erect new wind turbine towers, but alsoto dismantle or carry out maintenance on existing towers. Where thetower is new-build, purpose built attachment points can be providedwithin the tower sections to ensure anchorage of the jacking crane.However, where the tower is already erected a secure anchorage may beprovided either by using fixed attachment points or without fixedattachment points.

In one embodiment a secure anchorage is provided by employing one ormore clamps that grip the tower sections by compression and frictionalone. Contact pads made of a compliant material such as Polyurethaneare brought into contact with the tower section and pressure is appliedsufficient to develop the vertical frictional resistance necessary tosupport the desired loads.

An important aspect of these clamps lies in the fact that adjustment isprovided within the clamps and support structure to accommodate changesin the shape of the tower being climbed, and to ensure verticality inthe climbing frame at all times. The adjustment should include as aminimum for the pronounced taper currently employed in wind turbinetower designs.

The compliant pads may be mounted on a flexible backing substrate thatis tensioned at its ends. To allow for a more even distribution of theloads imposed by the clamp, the flexible substrate should contact thetower in a number of sections. In the embodiment shown in FIGS. 47 to58, four equal (quadrant) sections are shown, although it will beappreciated that the number is not restricted.

Each clamp is mounted on an arrangement of struts, ties and beams thatcan be adjusted to accommodate changes in the tower cross section, andthat can be locked to provide a fail-safe operation. Adjustment of thelength of the flexible substrate can be achieved by passing its endsaround rollers or sprockets that can rotate as the length is increasedor decreased. Preferably these sections of the flexible substratecomprise an arrangement of links similar to the tracks of a trackedvehicle, and are also covered with compliant material. An arrangement ofscrew-jacks between the sprocket wheels of adjacent sections of flexiblesubstrate allows tension to be applied and the length of substrate to beadjusted whilst allowing an efficient load path of hoop tension withinthe flexible substrate/sprocket wheel system.

Further more the friction coefficient of the tower/clamp interface canbe improved by preparing the relevant sections of tower with high-gripsurfaces such as anti-slip paint and glue-on grip strips.

A further safety feature which may be provided is the inclusion ofmechanical toothed wedges that can be activated as necessary that engageby a wedging action between the tower and climbing frame.

Once the jacking crane 5 and nacelle 6 are in position on the foundationplatform 3 the installation tower can be erected. An important aspect ofthe present invention is that the tower is supplied in manageablesections. These may be around 10 to 25 metres in length, and offshorecan be transferred onto the foundation platform in the same manner asthe jacking system. As the tower is supplied in sections the vessel 1can be smaller than conventionally used or proposed for offshore windfarm construction as it will not have to carry or tow a largecumbersome, unitary or two parts pre-made tower unit. As the decks ofthese vessels are frequently very obstructed and congested in any event,this is a significant advantage. A tower section 7 is transferred ontothe platform 3 and can be positioned within the jacking crane usinghydraulic means 8 as shown in FIGS. 6 and 7. Once first section 7 is inposition, a second tower section 9 can be transferred onto thefoundation platform 3 as shown in FIG. 8.

A crane 10 in the nacelle 6 can be used to perform all the liftingoperation after the initial lift of the sections from vessel 1. In afirst embodiment this may be achieved by allowing the nacelle 6 torotate while it is temporarily installed on top of the jacking crane 5.In an alternative embodiment a temporary boom (not shown) is attached tothe jacking crane 5. In either case the winch 10 can be located withinthe nacelle 6. A boom may also be required to enable the crane to reachover the side of the foundation platform to be able to lift the towersections (located around the side of the foundation platform) and alsothe blades in the supply boat. The boom may require a counterbalance.This can be achieving using a seawater ballast, again removing therequirement for a large lift.

The jacking crane 5 may simply be considered as a device for safelyclimbing the tower as it is constructed from the tower sections. Inother words, the jacking crane climbs the tower during construction.Initially it is used for installing tower sections as shown in FIGS. 7to 23. The jacking crane is also used to erect the nacelle and then theblades 11 and 12 as shown in FIGS. 24 to 30. Whilst the depictedembodiment uses two blades it will be appreciated that the number ofblades mounted on the tower is not restricted to this. The jacking crane5 moves up the tower as it is erected and is used to install a sectionof the tower on top of those section which have previously beeninstalled, using the crane 10 of the nacelle 6, which lifts the sectionsup to the jacking crane 5. The jacking crane 5 can subsequently be usedfor inspection (e.g. non-destructive testing of the tower and blades tolook for cracks), painting, replacing parts (e.g. blades) and any formof maintenance requiring access up the outside of the tower. All thesedifferent activities will require specially designed tools and liftingbaskets that have a common interface so they can simply by plugged intothe jacking crane.

The jacking crane 5, is anchored and used to combine the tower sectionsthat make up the tower. The jacking crane 5 carries a framework 35 suchas an ‘A’ frame (tool) or knuckle boom crane (tool) capable of plumbingor reaching inside the nacelle 6 so as to enable nacelle components tobe removed for maintenance or to be replaced completely. This is shownin FIGS. 59 to 61. In FIG. 59 the “A” frame has a runway beam which isplumbed over the nacelle centreline.

In an alternative embodiment the jacking crane may carry an ‘A’ framethat is capable of lifting the assembled nacelle or of lifting thelargest sub assemblies of the nacelle such that the nacelle is liftedafter the tower is completed instead of being carried by the jackingcrane during installation of the tower sections (as shown in FIG. 63).This alternative “A” frame configuration can also be used formaintenance and it may need to be extendible to allow removed componentsto be lowered passed to back of the nacelle. This is shown in FIGS. 62to 67.

The advantage of using an “A” frame to install the nacelle, rather thanlifting the nacelle with the jacking crane, is that it allows for muchlonger hydraulic rams in the jacking unit. This is because the “A” frameis much lighter than the nacelle and the reduced buckling loads thenallow greater extension, providing sufficient clearance for full lengthtower sections to be installed. It is likely that the tower will notneed to be modified significantly when compared with conventional towerinstallation using a crane.

The tower sections themselves are typically air and water-tight and inone embodiment suited to offshore applications may actually be attachedto the foundation platform 3 when it is floated to position. In thismanner they may be used to control buoyancy—i.e. an integral part of theinstallation process. The tower sections can be flooded when theplatform has reached location. This may aid installation of the platformby providing added weight.

The jacking crane 5 has a fail-safe mechanism that prevents it frombecoming detached from the tower under construction and falling. Thejacking crane may also be used for maintenance purposes and to providewelfare facilities for construction and/or maintenance personnel.

The jacking crane can be connected to a variety of interface tools andthus adapted for multiplicity. For example, the jacking unit may beadapted to carry tools, which are used for inspection and/or replacementof the blades, nacelle or tower sections. The jacking crane may includean access platform and a variety of tools.

It is also possible that the erection process described herein can byautomated to a significant degree. This may be achieved using remotecontrol and further improves safety and reduces costs. The design of theself installing tower facilitates maintenance and decommissioning worksand thus is particularly useful for inspecting blades and replacing ifnecessary.

In a second embodiment of the present invention, depicted in FIGS. 31 to46, tower sections 13 are pre-mounted or attached onto an foundationplatform 14, and towed into an offshore position by a transportationvessel 15. In this embodiment, it is of a particular advantage that thetower sections 13 are air and water-tight and buoyant, and thus helptransportation of the foundation platform to its offshore position. Oncethe foundation platform has been towed to its position, it is anchored16 onto the seabed, and the transportation vessel 15 will depart fromthe area. As the capital and operational costs of these vessels makethem hugely expensive, it will be appreciated that this is a significantadvantage over existing methods.

In a preferred embodiment, the foundation platform is of the typedescribed in the Applicant's co-pending UK Patent Application No0206569.6 and International Application No GB2003/001159, and isanchored to the ocean bed in the manner described in these earlierApplications.

Referring to FIG. 33, once the foundation platform has been anchoredonto the seabed, a transportation vessel carrying the jacking cranes 17and nacelle 18 arrives. A transportation vessel has a crane 19 which canbe used to lift the jacking crane 17 and nacelle 18 onto the foundationplatform, as shown in FIG. 34. The transportation vessel may then beremoved, as shown in FIG. 35, leaving the foundation platform with theentire apparatus required to install a wind turbine. Erection of thewind turbine may be fully operated and may be controlled by remotecontrol. Advantageously, the following steps can be carried out afterthe transportation vessel 15 has been removed, thus greatly reducingcosts.

Referring now to FIGS. 36 to 46, the jacking crane 17 is extended on thefoundation platform 14, thereby lifting nacelle 18, as shown in FIGS. 36to 37. Nacelle 18 has a winch or crane 19 which is activated and used towinch up tower sections 20 and 21 from their location on the foundationplatform 14, as shown in FIG. 38. From the position shown in FIG. 38,tower section 20 can be moved into position within the jacking crane 17and in the centre of foundation platform 14 using hydraulic moving part22, as shown in FIG. 39. Once tower section 20 is in position on thefoundation platform within the jacking crane 17, the jacking crane canbe further extended, as shown in FIG. 40. The crane or winch 19 canthereafter be used to winch up tower section 21, as shown in FIGS. 40 to41, and then moved into position within the jacking crane 17 on top offirst tower section 20 by a hydraulic moving part 22. Thus, towersections 20 and 21 are transferred into position within the jackingcrane 17, as shown in FIG. 42 to produce the beginning of turbine tower23.

This process can be repeated using further tower sections, as shown at24 and 25 in FIGS. 42 to 45, until the complete tower 23 is erected, asshown in FIG. 46. Following erection of the tower 23, the turbine bladescan be erected in the manner previously described.

It will be appreciated that whilst the depicted embodiment for towersections 20, 21, 24 and 25 are illustrated, the number of tower sectionsis not limited to this.

It is also recognised that an alternative option is to load or attachnot only the tower sections, but also the jacking crane and nacelle ontothe foundation platform 14 before it is towed into a location bytransportation vessel 15. This will completely eliminate the need forthe transportation vessel to be present near the foundation platform atany stage after the initial towing process, and will greatly reducecosts. In this option, the size of the foundation platform may beincreased, or may comprise a temporary extension to allow room for adrilling unit 26 to anchor the platform, together with the remainder ofthe apparatus.

Referring now to FIGS. 47 to 58 a further method of installing theapparatus described in the present invention on an foundation platformor other foundation 27 is illustrated.

The nacelle 28, tower sections and jacking crane are transported over anfoundation platform or other foundation using a transport vehicle 29 asshown in FIG. 47 and the nacelle is lifted onto the foundation platformor other foundation. The transport vehicle may then be removed. A crane30 can then be assembled as shown in FIGS. 50 and 51 for use in winchingthe tower sections into position. The nacelle can the be temporarilysupported whilst the jacking crane 31 is assembled and/or placed inposition, as shown in FIG. 52. The jacking crane is then extended. Thetower sections can then be delivered to the foundation platform orfoundation using a transport vehicle, as shown in FIG. 53.

In order to erect the wind turbine tower a first tower section 32 iswinched from the transport vehicle using the crane (FIG. 54). Thissection is then slid into position within the jacking crane using thecrane (FIG. 55). The first tower section can thereafter be used tosupport the nacelle whilst the jacking crane is adjusted to provideclearance blocks at 33 for one or more clamps 34 which are used tosafely and securely attach the jacking crane to the tower. This is shownin FIGS. 56 and 57. This process is then repeated with further towersections to erect a tower having the nacelle located at the top, onwhich turbine blades can be mounted. In the example embodiment andoutline procedure for erecting a wind turbine is as follows:

-   (a) The nacelle and hub is delivered over the foundation (or    assembled there if it is very large) and the jacking crane is    assembled around it using a small site crane.-   (b) The jacks lift the nacelle off the transporter or support    platform to a height sufficient for the onboard cranes to upend and    insert a tower section directly beneath the nacelle.-   (c) The jacks extend further to make space for a second tower    section, and the upper grippers engage with the top of the first    tower section.-   (d) The second section is lifted, inserted, and bolted to the first.-   (e) The upper grips now release and the jacks extend slightly so    that the upper grippers now engage with the bottom of the newly    installed upper tower section.-   (f) With the upper set of grippers locked, the jacks contract to    bring a bottom set of grippers to engage with the top of the lower    section of tower.-   (g) The top set of grippers can now release and the jacking crane    extends to make space for the third tower section. The upper grips    engage with the top of the tower before the next section is fitted.-   (h) The process repeats from step (c) until the tower is complete.-   (i) When the tower is complete, the jacks lower the nacelle onto the    tower for bolting, and the onboard cranes lift the blades into the    hub for bolting.

It will be appreciated that there are fundamental differences betweenthe jacking crane and a conventional crane. A conventional crane isoptimised for flexibility, whilst the jacking crane is designed for aspecific task—to erect large wind turbines. In practice this means:

-   -   there is no need for a road-going chassis—it only climbs towers.    -   there is no need for a slew capability.    -   the hook is replaced by a transfer carriage in the top-works of        the jacking crane to provide precision handling and mechanical        control at all times.

An advantage of the jacking system herein described lies in the factthat it can be used, not only to erect and disassemble towers, but canalso be used to climb existing towers for maintenance. A particularadvantage of the present invention lies in the fact that the windturbine can be erected in its entirety (including the erection of thetower, nacelle and blades) in an offshore location, without therequirement for a specialist vessel is required to be in attendance. Asa consequence lifetime costs are greatly reduced. In addition theprocess has desirable reversibility and thus the wind turbine can beremoved, or the blades, nacelle or indeed tower can be replaced ifrequired. This facilitates ongoing maintenance. The apparatus describedherein and in the Applicant's co-pending UK Application No 0206569.6 andInternational Application No GB2003/001159 is also self sufficient, inother words all of the delicate lifting and handling operations arecontrolled from the already constructed structure. The vessel maytherefore deliver the jacking mechanism and the tower sections and leaveand does not need to remain in the area. Components are landed onto thefoundation platform in a conventional way, but from there they arehandled by handling equipment that is supported by the already erectedstructure. This eliminates relative movement (e.g. between vessel hookand structure) which makes the operation safer and eliminates therequirement for massive offshore cranes.

A further advantage is that erection of the self installing turbine isinherently safer than convention methods because all of the lifts arecontrolled and do not require high unsupported loads. Thus the safety ofthe construction crew is ensured. The apparatus brings significant costsavings by eliminating the requirement for large cranes both on andoffshore, and is less sensitive to weather and geotechnical conditions.This is of particular advantage as offshore work will not be disruptedby sea state (tide and waves or wide).

A yet further important advantage lies in the use of one or more clampswhich ensure that the jacking crane is securely and safely attached tothe tower or tower sections. Other advantages are inherent in thedescribed apparatus as a low cost crane is used, the tower sections areeasier to handle and transport, the cost and time of erection isminimised and the apparatus can also be used for the maintenance ofexisting turbines, as well as building new turbines.

Various modifications may be made to the invention herein described,without departing from the scope thereof.

1. Apparatus for use in the onshore and offshore wind farm industry,said apparatus comprising a jacking crane and a plurality of towersections adapted to be combined to form a tower on which a nacelle andone or more blades are mounted, wherein the jacking crane is adapted tobe extended and climb upwards on the tower as the tower is erected fromthe tower sections and is used to position each of the tower sectionsduring erection, and is further adapted to mount the nacelle and one ormore blades the tower. 2-7. (canceled)
 8. Apparatus as claimed in claim1, wherein the nacelle is positioned on top of the jacking crane. 9.(canceled)
 10. Apparatus as claimed in claim 1, wherein the jackingcrane comprises a number of legs capable of being extended andretracted. 11-13. (canceled)
 14. Apparatus as claimed in claim 1,wherein the tower sections are buoyant.
 15. (canceled)
 16. Apparatus asclaimed in claim 1, wherein the jacking crane has a winch adapted tolift each of the tower sections into a position on top of a previoustower section.
 17. Apparatus as claimed in claim 16, wherein the winchis located within the nacelle. 18-19. (canceled)
 20. Apparatus asclaimed in claim 1, wherein the nacelle rotates on top of the jackingcrane to facilitate lifting operations.
 21. Apparatus as claimed inclaim 1, wherein the nacelle is equipped with a winch or crane adaptedto assist with the installation of the nacelle or blades and theirsubsequent maintenance or replacement. 22-24. (canceled)
 25. Apparatusas claimed in claim 1, wherein the tower sections are provided withpurpose built attachment points, which are adapted to receive thejacking mechanism.
 26. Apparatus as claimed in claim 25, wherein thepurpose built attachment points are pockets.
 27. (canceled) 28.Apparatus as claimed in claim 1, wherein the jacking crane has one ormore clamps which engage the tower sections by compression and friction.29-32. (canceled)
 33. Apparatus as claimed in claim 28, wherein the oneor more clamps are mounted on an arrangement of struts, ties and beamswhich are capable of being adjusted to accommodate a change in the crosssection of the tower or tower sections.
 34. Apparatus for use in theonshore and offshore wind farm industry, said apparatus comprising ajacking crane and a plurality of tower sections which can be combined toerect a tower on which a nacelle and one or more blades can be mountedusing the same jacking crane, wherein the jacking crane comprises afriction clamp having a flexible backing substrate that is tensioned atthe ends.
 35. Apparatus as claimed in claim 34, wherein the flexiblebacking substrate contacts the tower in a plurality of locations orsections to provide even distribution of load.
 36. Apparatus as claimedin claim 34, wherein the length of the flexible backing substrate can bealtered to ensure the clamp maintains a secure fit to the tower. 37.Apparatus as claimed in claim 36, wherein the length of the flexiblebacking substrate is adjusted using rollers or sprockets.
 38. Apparatusas claimed in claim 37, wherein the ends of the flexible substrate aremade from or covered with a compliant material, and are adapted to bepassed around the rollers or sprockets which rotate as the length of thesubstrate is altered. 39-40. (canceled)
 41. Apparatus as claimed inclaim 34, wherein the tower sections have a high grip surface achievedby the use of anti-slip paint or glue-on grip strips. 42-51. (canceled)52. Apparatus as claimed in claim 1 wherein the jacking crane comprisesfacilities for construction or maintenance personnel. 53-68. (canceled)69. A jacking crane the for use in the construction of wind turbineapparatus for the onshore and offshore wind farm industry, said jackingcrane comprising: means for positioning a plurality of tower sections toform a tower; a jacking mechanism adapted to be extended and climbupwards on the tower as the tower is erected from the tower sections,and; means for carrying a nacelle on the jacking crane as the as thetower is erected.
 70. A jacking crane the for use in the construction ofwind turbine apparatus for the onshore and offshore wind farm industry,said jacking crane comprising: means for positioning a plurality oftower sections to form a tower; a jacking mechanism adapted to beextended and climb upwards on the tower as the tower is erected from thetower sections, and; a friction clamp having a flexible backingsubstrate which contacts the tower in a plurality of locations orsections to provide even distribution of load.
 71. A method ofconstructing wind turbine apparatus for the onshore and offshore windfarm industry, the method comprising the steps of: a. Providing ajacking crane and a nacelle on a foundation platform, the nacelle beingpositioned on the jacking crane; b. Erecting a tower from a plurality oftower sections by positioning each tower section using the jackingcrane; c. Extending the jacking crane to climb up the tower as the toweris erected while carrying the nacelle on the jacking crane; and d.Installing the nacelle on top of the erected tower.
 72. The method asclaimed in claim 71, wherein the method is automated.
 73. The method asclaimed in claim 71, wherein the method is controlled by remote control.